The prior art includes brake drums for vehicles, including medium and heavy-duty trucks, trailers and buses. In order to slow or stop a moving vehicle, the braking mechanism is activated to urge the brake shoes and brake lining into engagement with the friction surface of the brake drum. The frictional engagement of the brake lining with the brake drum causes the vehicle to slow or stop. However, in the process, the kinetic energy of the moving vehicle is converted into heat. Further, the frictional engagement causes wear on the brake lining which produces debris in the form of brake dust. Over time, a substantial amount of brake dust may accumulate within the brake drum and surrounding area. The accumulation of brake dust impairs the performance of the brake system, such as reducing the effectiveness to dissipate heat, and creating noise during operation of the brake system. Still further, road debris enters the brake drum and further impairs performance of the brake drum.
The prior art includes various means for providing and enhancing cooling and ventilation to the brake drum, in order to remove the heat, debris and lessen noise. For example, U.S. Pat. No. 3,127,959 is directed to a cooling device for brake drums and shoes. The cooling device is installed within the brake drum. In particular, the cooling device includes a disc, the body of which is provided with a plurality of vanes which form air circulating blades when the disc is rotated. The disc is placed over the outer diameter of the wheel hub. The brake drum is then installed and receives the disc within a cavity formed by the brake drum. A magnet secured to the disc draws and holds the disc axially of the drum by magnetic force on the hub flange. U.S. Pat. No. 4,989,697 is directed to a cooling, cleaning and drying means for brake drums. In particular, a generally circular elongated flexible air scoop strip is provided and includes mounting holes and outwardly protruding air scoops. The strip is mounted within the brake drum and secured in place via bolts which extend through the mounting holes and through the brake drum.
The prior art also includes cooling devices which are installed on an exterior surface of the brake drum. For example, U.S. Pat. No. 2,896,749 discloses a brake drum cooling device having a plurality of ring segments joined together at their ends by means of turnbuckles. The turnbuckles serve to clamp the segments against the outer surface of the flange of a brake drum. U.S. Pat. No. 2,659,459 discloses a brake cooling ring which is secured to the outer surface of the brake drum via bolts which extend from the hub and through the brake drum.
It is also known to provide full cast transit brake drums with vent openings.
While advancements have been made to address the foregoing and other related problems, there still exists a need for further improvements.